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Yoga Health Secrets  | Food for Thought  | Eating Meat isn't natural  |  Fasting


Eating meat isn't natural

Why humans are primarily plant-eaters by design

by Michael Bluejay

A fair look at the evidence shows that humans are optimized for eating exclusively plant foods, and not meat. Consider:

  • Human anatomy: We're most similar to other herbivores, and drastically different from carnivores.

  • Longevity & health: There's a direct correlation between the amount of meat you eat and the amount of illness you suffer. Meat is poison to us. It's the primary reason we get heart disease, cancer, diabetes, osteoporosis, and every other major degenerative disease. If eating meat were natural, it wouldn't make us so sick.

  • Physical performance: People have much better endurance when they don't eat meat -- whether they're professional athletes or normal people.

Clearly we're capable of eating meat. But that doesn't mean it's natural. You can dress a monkey up in a cute little suit and teach it to perform circus tricks, but just because it can doesn't mean that it's natural -- nor that it should. When I say that meat-eating is unnatural, I mean simply that our bodies aren't optimized to have it be a normal part of our diets -- and we suffer the consequences when we make it so.

The meat-eating reader already has half a dozen objections to this before (s)he's even read the rest of the article, and I will address those objections specifically, but first let me address them generally: It is human nature to want to feel that what we're doing is right, proper, and logical. When we're confronted with something that

Vegan bodybuilder, Kenneth Williams. Shattering the myth that vegans are skinny and malnourished.

suggests that our current practices are not the best ones, it's uncomfortable. We can either consider that our choices may not have been the best ones, which is extremely disturbing, or we can reject that premise without truly considering it, so that we don't have to feel bad about our actions. That's the more comfortable approach. And we do this by searching our minds for any arguments we can for why the challenge must be wrong, to justify our current behavior.

Think about that for a moment: Our feeling that our current actions are correct isn't based on our arguments. Rather, our actions come first and then we come up with the arguments to try to support those actions. If we were truly logical, we'd consider the evidence first and then decide the best course of action. But often we have it in reverse, because it's too difficult to accept that we might have been wrong.

This is particularly true when it comes to vegetarianism. It is quite easy to identify because the anti-vegetarian arguments are usually so weak and desperate, compared to other kinds of discourse. A person who would never normally suggest something so fantastic as the idea that plants can think and feel pain, will suddenly all but lunge for such an argument when they feel their meat-eating ways are being questioned. It's human nature.

At an earlier point in my life, I was in the same position as you probably are. My habits were challenged by a book I ran across in the library called Going Vegetarian. I didn't want to consider it fairly, because I wanted to keep eating meat. I'd grown up eating it, and I liked it. And there was another reason: I'd grown up in a small farming community raising and killing chickens. Accepting the book's premise really meant that I'd have to admit that I might not have made the best choices. So I came up with various weak defenses to justify my behavior. But deep down I knew I was kidding myself, and practicing a form of intellectual cowardice. When I considered the arguments honestly, I stopped eating animals. That was over 20 years ago and it was absolutely the best decision I ever made.

But haven't humans always eaten meat?

I can't think of a better example of a case in which people believe something to be true just because they assume it is. We all grew up thinking that our ancestors were meat-eaters, but where did we get that idea? Is it true just because it's part of our collective consciousness? More importantly, what does the evidence say?

John A. McDougall, M.D., perhaps the most knowledgeable expert on the relationship between diet and disease, asserts that our early ancestors from at least four million years ago followed diets almost exclusively of plant foods. Many other scientists believe that early humans were largely vegetarian. (See articles by David Popovich and Derek Wall.) This is important because while prehistoric peoples hunted animals, that is still a relatively recent development in the long period of human existence. Certainly not long enough for our bodies to have adapted to it from evolution. Here's some evidence: The Maasai in Kenya, who still eat a diet high in wild hunted meats, have the worst life expectancy in the world. (Fuhrman)

There's another important fact never acknowledged by meat proponents: Humans act by idea rather than by instinct. Other animals are programmed to know what food is. We are not. For us, it's learned behavior. Or in some cases, guessed behavior. We can make choices about what we should eat even if that's contrary to good health, as millions prove every day when they eat at McDonald's. If our ancestors ate meat, they were simply being human and making choices rather than acting on instinct. Think about it: Do you really believe that cavemen were true experts about nutrition? If so, what other major decisions about your life would you like to put in the hands of a caveman?

What it means to be an omnivore

There is no question that humans are capable of digesting meat. But just because we can digest animals does not mean we're supposed to, or that it will be good for us. We can digest cardboard. That does not mean we should.

If the evidence shows that our anatomy favors the digestion of plant foods, and we're healthier when we eat less animal foods, what do we make of the fact that we're capable of eating animals? It's simple: We have the ability to eat a wide variety of foods as a survival mechanism. The fact that we can eat just about anything, including meat, is very handy, from a biological point of view. But the fact that we're able to doesn't mean that we're designed to. The evidence for this is that our biology is similar to that of other herbivores, and the more animal foods we incorporate into our diets, the more our health suffers. In fact, it is rather specious to claim that humans are natural meat-eaters considering how poorly we fare when we do so.

McDougall explains how the ability to digest animal foods didn't hurt our survival as a race, although it takes a toll on our lifespan:

"Undoubtedly, all of these [meat-containing] diets were adequate to support growth and life to an age of successful reproduction. To bear and raise offspring you only need to live for 20 to 30 years, and fortuitously, the average life expectancy for these people was just that. The few populations of hunter-gatherers surviving into the 21st Century are confined to the most remote regions of our planet &endash;- like the Arctic and the jungles of South America and Africa &endash;- some of the most challenging places to manage to survive. Their life expectancy is also limited to 25 to 30 years and infant mortality is 40% to 50%. Hunter-gatherer societies fortunately did survive, but considering their arduous struggle and short lifespan, I would not rank them among successful societies."

Finally, our physiology is much more similar to that of other plant-eaters than it is of true omnivores, as we'll see shortly.

Considering the other primates

Our closest animal relatives are primates. They provide clues about our ideal diet since our anatomy is so similar. Very few of them eat animals, and those who do typically stick to things like insects, not cows, pigs, and chickens. Jane Goodall, famous for her extensive study of apes while living with them, found that it was very rare for the primates she saw to eat other animals. Critics lunge all over the fact that Goodall discovered that primates occasionally eat meat. But the key word here is occasionally. If we ate meat is infrequently as the other primates did, our health would be a lot better. Goodall herself apparently wasn't impressed by primates' occasional eating of meat: Jane Goodall is a vegetarian.


Humans lack a desire to eat whole animals

True carnivores (and omnivores) get excited about eating whole prey animals when they see them. Humans do not. We're interested in eating the body parts only because they've been removed from the original animal and processed, and because we grew up eating them, making it seem perfectly normal. It's amazing how much of a disconnect we've been able to learn about the difference between animals and food. As GoVeg puts it:
While carnivores take pleasure in killing animals and eating their raw flesh, any human who killed an animal with his or her bare hands and dug into the raw corpse would be considered deranged. Carnivorous animals are aroused by the scent of blood and the thrill of the chase. Most humans, on the other hand, are revolted by the sight of raw flesh and cannot tolerate hearing the screams of animals being ripped apart and killed. The bloody reality of eating animals is innately repulsive to us, more proof that we were not designed to eat meat.

Ask yourself:
When you see dead animals on the side of the road, are you tempted to stop for a snack?
Does the sight of a dead bird make you salivate?
Do you daydream about killing cows with your bare hands and eating them raw?

If you answered "no" to all of these questions, congratulations; you're a normal human herbivore; like it or not. Humans were simply not designed to eat meat. Humans lack both the physical characteristics of carnivores and the instinct that drives them to kill animals and devour their raw carcasses.

Comparing humans to other animals

Human physiology is strikingly similar to that of other plant-eaters, and quite unlike that of carnivores. It is telling that in none of the horribly misspelled missives that readers have sent in to argue with me do they ever deny the data in the following table. They simply think that by making some other point (e.g., that humans possess canine teeth) that somehow obliterates the more convincing data in the table.

The following is from a book credited at the end.




has claws

no claws

no claws

no pores on skin; perspires through tongue to cool body

perspires through millions of pores on skin

perspires through millions of pores on skin

sharp, pointed front teeth to tear flesh

no sharp, pointed front teeth

no sharp, pointed front teeth

no flat back molar teeth to grind food

has flat, back molar teeth to grind food

has flat, back molar teeth to grind food

small salivary glands in the mouth (not needed to pre-digest grains and fruits)

well-developed salivary glands, needed to pre-digest grains and fruits

well-developed salivary glands, needed to pre-digest grains and fruits

acid saliva; no enzyme ptyalin to pre-digest grains

alkaline saliva; much ptyalin to pre-digest grains

alkaline saliva; much ptyalin to pre-digest grains

strong hydrochloric acid in stomach to digest tough animal muscle, bone, etc.

stomach acid 20 times weaker than that of meat-eaters

stomach acid 20 times weaker than that of meat-eaters

intestinal tract only 3 times body length, so rapidly decaying meat can pass out of body quickly

intestinal tract several times body length (plant foods decay slowly so can take their time to pass through the body)

intestinal tract several times body length


Carnivorous animals, including the lion, dog, wolf, cat, etc., have many unique characteristics which set them apart from all other members of the animal kingdom. They all possess a very simple and short digestive system -- only three times the length of their bodies. This is because flesh decays very rapidly, and the products of this decay quickly poison the bloodstream if they remain too long in the body. So a short digestive tract was evolved for rapid expulsion of putrefactive bacteria from decomposing flesh, as well as stomachs with ten times as much hydrochloric acid as non-carnivorous animals (to digest fibrous tissue and bones). Meat-eating animals that hunt in the cool of the night and sleep during the day when it is hot do not need sweat glands to cool their bodies; they therefore do not perspire through their skin, but rather they sweat through their tongues. On the other hand, vegetarian animals, such as the cow, horse, zebra, deer, etc., spend much of their time in the sun gathering their food, and they freely perspire through their skin to cool their bodies. But the most significant difference between the natural meat-eaters and other animals is their teeth. Along with sharp claws, all meat-eaters, since they have to kill mainly with their teeth; possess powerful jaws and pointed, elongated, "canine" teeth to pierce tough hide and to spear and tear flesh. They do NOT have molars (flat, back teeth) which vegetarian animals need for grinding their food. Unlike grains, flesh does not need to be chewed in the mouth to predigest it; it is digested mostly in the stomach and the intestines. A cat, for example, can hardly chew at all.


Grass-and-leaf-eating animals (elephant, cow, sheep, llama, etc.) live on grass, herbs, and other plants, much of which is coarse and bulky. The digestion of this type of food starts in the mouth with the enzyme ptyalin in the saliva. these foods must be chewed well and thoroughly mixed with ptyalin in order to be broken down. For this reason, grass-and-leaf eaters have 24 special "molar" teeth and a slight side-to-side motion to grind their food, as opposed to the exclusively up-and-down motion of carnivores. They have no claws or sharp teeth; they drink by sucking water up into their mouths as opposed to lapping it up with their tongue which all meat eaters do. Since they do not eat rapidly decaying foods like the meat eaters, and since their food can take a longer time to pass through, they have much longer digestive systems -- intestines which are ten times the length of the body. Interestingly, recent studies have shown that a meat diet has an extremely harmful effect on these grass-and-leaf eaters. Dr. William Collins, a scientist in the New York Maimonedes Medical Center, found that the meat-eating animals have an "almost unlimited capacity to handle saturated fats and cholesterol". If a half pound of animal fat is added daily over a long period of time to a rabbit's diet, after two month his blood vessels become caked with fat and the serious disease called atherosclerosis develops. human digestive systems, like the rabbit's, are also not designed to digest meat, and they become diseased the more they eat it, as we will later see.

Fruit-eaters include mainly the anthropoid apes, humanity's immediate animal ancestors. The diet of these apes consists mostly of fruit and nuts. Their skin has millions of pores for sweating, and they also have molars to grind and chew their food; their saliva is alkaline, and, like the grass-and-leaf eaters, it contains ptyalin for predigestion. Their intestines are extremely convoluted and are twelve times the length of their body, for the slow digestion of fruits and vegetables.

Human Beings

Human characteristics are in every way like the fruit eaters, very similar to the grass- eater, and very unlike the meat eaters, as is clearly shown in the table above. The human digestive system, tooth and jaw structure, and bodily functions are completely different from carnivorous animals. As in the case of the anthropoid ape, the human digestive system is twelve times the length of the body; our skin has millions of tiny pores to evaporate water and cool the body by sweating; we drink water by suction like all other vegetarian animals; our tooth and jaw structure is vegetarian; and our saliva is alkaline and contains ptyalin for predigestion of grains. Human beings clearly are not carnivores by physiology -- our anatomy and digestive system show that we must have evolved for millions of years living on fruits, nuts, grains, and vegetables.

Furthermore, it is obvious that our natural instincts are non-carnivorous. Most people have other people kill their meat for them and would be sickened if they had to do the killing themselves. Instead of eating raw meat as all flesh-eating animals do, humans boil, bake, or fry it and disguise it with all kinds of sauces and spices so that it bears no resemblance to its raw state. One scientist explains it this way: "A cat will salivate with hungry desire at the smell of a piece of raw flesh but not at all at the smell of fruit. If man could delight in pouncing upon a bird, tear its still-living limbs apart with his teeth, and suck the warm blood, one might conclude that nature provided him with meat-eating instinct. On the other hand, a bunch of luscious grapes makes his mouth water, and even in the absence of hunger he will eat fruit because it tastes so good."

Scientists and naturalists, including the great Charles Darwin who gave the theory of evolution, agree that early humans were fruit and vegetable eaters and that throughout history our anatomy has not changed. The great Swedish scientist Carl von Linné states: "Man's structure, external and internal, compared with that of the other animals, shows that fruit and succulent vegetables constitute his natural food."

So it is clear from scientific studies that physiologically, anatomically, and instinctively, man is perfectly suited to a diet for fruit, vegetables, nuts, and grains. This is summarized in the table above.

from What's Wrong with Eating Meat,
by Barbara Parham, ©Ananda Marga Publications, 1979

As another author said, "The human body was not designed to catch or eat animals. You have no claws. Your teeth do not rend flesh. Your mouth can not seriously wound nor is it made to really get a good bite into a struggling victim like true carnivores can. You are not fit to run fast to catch prey. Meat-eaters have fast enough reflexes to ambush or overtake a victim. You do not. Try catching a pig or a chicken with your bare hands; see what happens."


"But what about canine teeth and binocular vision?"

It's part of our collective consciousness that we have "canine teeth" and that this "proves" that we're meat eaters. But the truth is that this argument couldn't be weaker.

Humans' so-called "canine teeth" are unlike the canine teeth of actual canines, which are really long and really pointed. Our teeth are absolutely not like theirs. In fact, other vegetarian animals (like gorillas and horses) possess the same so-called "canine" teeth.

Overall, our teeth resemble those of plant-eaters much more than meat-eaters. For example, we have molar teeth (plant-eaters do, carnivores don't). Try to find a human-type molar inside your cat's mouth. Our teeth can also move side to side to grind, just like the other plant-eaters, and completely unlike the carnivores. Their jaws go only up and down.

My favorite quote from when someone brought up the canine rationalization on a message board:

"Hey Julia--we evolved with canine teeth? I'd like to see you tackle a steer and tear it apart with those ferocious incisors."

What's funny to me is how the teeth argument is so important to meat proponents when they make their point about canine teeth, and then as soon as they find out that our teeth are much more similar to those of herbivores than of carnivores, and therefore consideration of our teeth suggests that we're designed to be plant eaters -- suddenly what kind of teeth we have is not so important to them after all.

Others have argued that predators have eyes on the front of their heads for binocular vision, while prey animals have eyes on the sides, indicating that we fall into the predator camp. This ignores the fact that the animals that we're most similar to -- the other primates -- have eyes on the front of their heads, and are almost exclusively vegetarian. It's also important to remember what I said at the top of this article: There is certainly evidence on both sides of this debate, but the preponderance of evidence clearly shows that we're suited to eating plants almost exclusively.

If meat is so good for us, it wouldn't kill us

The medical evidence is overwhelming and indisputable: The more animal foods we eat, the more heart disease, cancer, diabetes, and other degenerative disease we suffer. This has been exhaustively demonstrated beyond any doubt. If it were natural for us to eat these foods, they wouldn't kill us. The fact that health can be regained by laying off meat and dairy is powerful evidence that we shouldn't have been eating those foods in the first place.

Dean Ornish, M.D. was the first person to prove that heart disease can be reversed, and he did so by feeding his patients a vegetarian diet. John McDougall, M.D. has also written extensively about how animal foods cause disease, and how people can regain their health by eating vegan instead. The esteemed T. Colin Campbell oversaw the most massive study of the relationship between diet and disease, the China Study, which the New York Times called "the grand prix of epidemiology". His conclusions are the same as the other experts: we're not designed to eat animal foods, because we get sick when we do so.

Human performance is highest on meat-free diets

Vegetarian and vegan athletes are at the top in their sports. Carl Lewis, the runner, won nine Olympic gold medals. Lewis says that he had his best performance as an athlete after he adopted a vegan diet. (source)

The famed bodybuilder, Andreas Cahling, is also vegan.

Ruth Heidrich, a vegan Ironman triathlete and marathon runner has racked up more than 700 first-place trophies and set several performance records. She was also named One of the 10 Fittest Women in North America.

Carl Lewis


Those who would object by saying that most top athletes eat meat can congratulate themselves for missing the point. The fact is that most Westerners are meat-eaters, because we've all grown up thinking it's good for us, and we like it. So of course most athletes are going to be meat-eaters too, since they're only human. These athletes perform well in spite of their diets, not because of them, and would undoubtedly perform even better if they ate less animal foods. And while reliable statistics are hard to come by, there is little doubt that athletes in general have been moving towards vegetarianism in large numbers over the past twenty years.

John Robbins wrote in Diet for a New America about how vegetarians have much more stamina and endurance than meat-eaters:

At Yale, Professor Irving Fisher designed a series of tests to compare the stamina and strength of meat-eaters against that of vegetarians. He selected men from three groups: meat-eating athletes, vegetarian athletes, and vegetarian sedentary subjects. Fisher reported the results of his study in the Yale Medical Journal.25 His findings do not seem to lend a great deal of credibility to the popular prejudices that hold meat to be a builder of strength.

"Of the three groups compared, the...flesh-eaters showed far less endurance than the abstainers (vegetarians), even when the latter were leading a sedentary life."26

Overall, the average score of the vegetarians was over double the average score of the meat-eaters, even though half of the vegetarians were sedentary people, while all of the meat-eaters tested were athletes. After analyzing all the factors that might have been involved in the results, Fisher concluded that:

"...the difference in endurance between the flesh-eaters and the abstainers (was due) entirely to the difference in their diet.... There is strong evidence that is conducive to endurance."27

A comparable study was done by Dr. J. Ioteyko of the Academie de Medicine of Paris.28 Dr. Ioteyko compared the endurance of vegetarian and meat-eaters from all walks of life in a variety of tests. The vegetarians averaged two to three times more stamina than the meat-eaters. Even more remarkably, they took only one-fifth the time to recover from exhaustion compared to their meat-eating rivals.

In 1968, a Danish team of researchers tested a group of men on a variety of diets, using a stationary bicycle to measure their strength and endurance. The men were fed a mixed diet of meat and vegetables for a period of time, and then tested on the bicycle. The average time they could pedal before muscle failure was 114 minutes. These same men at a later date were fed a diet high in meat, milk and eggs for a similar period and then re-tested on the bicycles. On the high meat diet, their pedaling time before muscle failure dropped dramatically--to an average of only 57 minutes. Later, these same men were switched to a strictly vegetarian diet, composed of grains, vegetables and fruits, and then tested on the bicycles. The lack f animal products didn't seem to hurt their performance--they pedaled an average of 167 minutes.29

Wherever and whenever tests of this nature have been done, the results have been similar. This does not lend a lot of support to the supposed association of meat with strength and stamina.

Doctors in Belgium systematically compared the number of times vegetarians and meat-eaters could squeeze a grip-meter. The vegetarians won handily with an average of 69, whilst the meat-eaters averaged only 38. As in all other studies which have measured muscle recovery time, here, too, the vegetarians bounced back from fatigue far more rapidly than did the meat-eaters.30

I know of many other studies in the medical literature which report similar findings. But I know of not a single one that has arrived at different results. As a result, I confess, it has gotten rather difficult for me to listen seriously to the meat industry proudly proclaiming "meat gives strength" in the face of overwhelming evidence to the contrary.

(more from this book)


  • Human anatomy is much more similar to herbivores than carnivores.
  • Meat consumption unquestionably promotes heart disease, cancer, diabetes, osteoporosis, and every other major degenerative disease.

Click here for links to Vegetarian web sites


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